Flexible polyurethane foams prepared from organic isocyanates and polyester polyols have general utility as resilient materials for furniture, cushions, mattresses, and upholstery. Polyurethane foams typically burn with ease and often emit dripping embers which tend to spread combustion.
It is known to improve the flammability of flexible foams by the use of halogenated organophosphorus flame retardants, such as those described in U.S. Pat. No. 3,041,293.
The use of specific amino resins and amino resin derivatives for inclusion in polyurethane foams has been described in the prior art. For example, U.S. Pat. No. 3,134,742 employs a synergistic combination of flame retardant ingredients wherein one ingredient is the reaction product of an acidic phosphorus compound and an amino compound. U.S. Pat. No. 3,135,707 describes polyurethane foams derived from partially alkylated polymethylolmelamines. U.S. Pat. No. 4,122,049 describes a polyurethane forming process using sedimenting dispersions of aminoplasts. U.S. Pat. No. 4,130,697 describes polyurethane foam systems wherein aminoplast precondensates are reacted with organic isocyanates. U.S. Pat. No. 4,139,501 describes melamine derivative amino resins incorporated into flexible polyurethane foams with optional halogenated organophosphorus compounds. U.S. Pat. No. 4,160,075 describes foams prepared from a reaction product of aminoplast precondensates and organic isocyanates.
Polyurethane foams containing halogenated organophosphorus compounds and urea-formaldehyde resin are described in applicant's copending application. Ser. No. 449,719, filed Dec. 14, 1982 now U.S. Pat. No. 4,433,071. A disadvantage of these urea-formaldehyde containing compositions is that they often emit a formaldehyde odor during cure.
It is desirable to develop new polyurethane foam additives which effectively enhance flame retardant and dripping ember retardant properties without excessive release of toxic fumes during foam formation.